SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4457ac216ac4b4945d62177e1ad414fdf2227858819ee4fe8b27d9b7bcde428' 
  AND token = 'djJN27PD4UE2WOGO36Bj/uyfqH3SQFmPZKrVUnzWddw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}